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W. H. McCLELMWD In.

HBCUH BREAKER. "memo" min APR. 15 m1.

Patented Sept. 2, 1919.

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i J w UNITED STATES PATENT OFFICE.

WILLIAM H. MOCLELLAND, JIL, OF WILKINSIBUBG, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH &; SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A. CORPORA- 'IION OF PENNSYLVANIA,

CIRCUIT-BREAKER.

Specification of Letters Patent.

Patented Sept. 2,1919.

Yb all whom it may concern:

Be it known that I, WILLIAM H. MoCLnL- LAND, Jr., a citizen of the United States, residing at Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Circuit-Breakers, of which the following is a specification.

My invention relates to circuit breakers and more particularly to thermo circuit breakers.

I will describe one form of circuit breaker and one form of apparatus employing the same, embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a view showing in elevation one form of circuit breaker embodying my invention, and one form of apparatus employing such circuit breaker and also embodying my invention, the apparatus, however, being shown only diagrammatically.

Referring to the drawing in detail, the circuit breaker, which is designated generally at C. comprises in this embodiment a base plate B and a top plate T, formed of insulating material and supported in spaced relation to the base plate by means of rods B. An L-shaped lever L located between the plates B and T at one end thereof is pivotally mounted for swinging movement upon an ear E formed on the base plate B. The long arm of the lever L is provided with insulating studs S upon which is socured a resilient contact finger F. This contact finger is adapted to enact with a sta-' tionary contact G mounted on anangle bar H, such bar being secured to the upper side of the plate T by a binding post P. Interposed between the short arm of the lever L and the base plate B is an expansible spring K, which spring serves to bias th lever L outwardly, that is, toward such position that the contact F-G is open. As shown in the drawing, the contact finger F is held, against the action of the spring K, in engagement with the contact G by means of a latching device generally indicated at D. The latching device D comprises in this instance a latching lever cl pivotally connected at one end to a link d, which latter in turn is pivotally mounted on the base plate B. The free end of the lever d is formed with a book 11 for engagement with a keeper d 'in a second bracket Z.

secured to the free end of the long arm of the lever L.

A designates a tripping arm for raising latching lever (l away from the lever L. This arm is pivoted at one of its ends to a bracket Z secured to and depending from the top plate T. The tripping arm A is biased upwardly by a contractile spring K, the lower end of the spring being connected to the lever adjacent the free end thereof While its upper end is connected to a screw V adjustably mounted in the top plate '1. A block Q, formed of insulating material is secured to the upper side of the lever A adjacent its free end to engage the latching lever (Z, such block acting as a spacing means for the levers, as will be understood. Up ward movement of the lever A is restricted by means of a thermostat X, which, as here shown, consists of a wire formed of a material having a large co-cflicient of expansion, such, for example, as German silver. One end of this wire passes freely through an openlng a, formed in the bracket Z, and is secured to a screw V adjustably mounted The opposite end of the wire is suitably secured to the outer end of the tripping lever A, as shown, such end, however, extending through a block J, secured to the lever whereby the wire is maintained in spaced relation to the lever A throughout its entire length. The brackets Z and Z are spaced apart by'a block Y formed of insulating material, and are provided with binding posts P and P respectively, arranged upon the upper side of the top plate T, as shown.

By connecting the binding posts P and I by a conducting wire W, it will be evident from the preceding description that the contact FG when closed is in electrical communication with the binding post P through wire W, post P arm A, wire X, and bracket Z.

As shown in the drawing, the circuit breaker G is in set position: that is the latching device D is in engagement with lever L so that the contact finger F is held in closed position. By properly adjusting the tension of the spring K and of the wire X, through the medium of their respective screws V and V, the forces exerted upon the tripping lever A by such members may be so con trolled that when current of a predetermined value or less flows in wire X. or when current of a higher value flow momentarily in this wire, the arm A is maintained in its inactive position. With the circuit breaker in this position, assume that current of greater than the predeterulined value flows through wire X for a mnsidi-rahle length of time. This current will heat the wire to such a degree that the expansion of the wire is sul'lirienl lo allow arm A lo rise and lift latch r] away from [he lo-eper thus al lowing contact l*-G to open. Current then ceases to How through wire X, so that this wire cools off and draws arm A down, allowing contact FG to again he closed in the operation hereinafter described.

In order to reset the breaker, I provide means which I will now describe. N designates a disk or Wheel which is adapted to be rotated by means of a reversible electric motor M. The disk N is o iteratively connected to the latching device by a link. .l one end of the link being (-ccentri ally mounted upon the disk while its opposite end is pivotally connected to the link (1'. Movement of the disk N either clockwise or counterclockwise is restricted to substantially one cycle by meam; of a in N formed on the periphery of the disk, which is adapt ed t engage a stop 0. From this construe tion and arrangement, it will be seen that when the motor isenergized to rotate in one direction or the other, rectilinear movement is imparted to the latching lever 61 through the medium of the disk N, rod .U and llnk d, as will be understood. .By viqtuepf this movement of the latching lever, it will be obvious that when the tripping lever A returns to its normal position dueto the cooling of the Wire X, as previously described, and the motor M is energized, the lat-clung lever is moved forward to cause the hook (I to engage the keeper (1, and then rearward to return the lever 14 and contact liuger F to their normal positions, as shown in the drawin It is to he noted that ;be-' fore the lever 1 can be returned to ,its nor mal position to close contact K -G it is nec essary that the thermostat X, and consequently the lever A, shall have returned to their normal positions, otherwise the latchin lever d ,when moved forwardly yvo uld fail to engage the lever L by reason of ,the fact that the tripping lever retains thelatrhing lever in a position above that in which it. can engage keeper d*.

I will now describe one form of apparatus employing the circuit breaker C, yr rich appparatus ,is, as here shown, a railway ,tra c controlling apparatus. he apparatus coinprises a railway switch 12, to which is connected an operating rod ,13. A ,pin L4 .is formed on the free endof the rod 13 and is adapted to ride .Withina cam slot 15 formed in a slide plate 16. An electric motorM' nnparts longitudinal movement to the 16 1 through the medium of a gear 17 fixed to the motor shaft 18 and meshing with lhe toothed edge 19 of the slide plate 16. Such movement of the plate 16 in either dire(.:tion causes the pin 14 to follow the course defined hy the slot 15, and thereby imparts rectilinear movement to the operating rod 123. By this operation switch 12 is shifted from normal position to reversi-i position or vice vorsu, according to the direction of movement of the slide plate to, as will he understood by those versed in the ar t.

In electrically-operated sw iteh movements of this character a cut-out svviteh for the motor M is usually provided to de'cnergize the motor after the switch has reached either of ,itseggtreme positions. The cut-out switch 1S Indicated generally at 100,and as here shown, comprises a bar 20 fixed to one end of the plate 16 for movement therewith, such bar helng formed with a longitudinally extending slot 21 ot' a length less than l'hat of the cam slot 15. A switch blade 22 pivoted at 23 is provided \vith a pin 21 which rides in the slot 21 so that when the bar 20 is moved by the plate 16 blade 22 will he moved to engage either of the contacts or 26 according to thedirection of movement of the bar. oivingyothe lcngtlrof the slot 21 and the location of the blade 22, the shifting of the blade em contact to contact does not occur until the slide plate 16 has nearly reached the end of its stroke so thatthe motor M ,rnay he maintained energized during transit of the s vvitch but will be dcenergized after the switch has reached either ov its egrtrenie positions.

A sourceof current such as a hatterv 27 supplies current to the motor A circuit controller indicated generally at 200, together with the cut-out switch 100, controls the supply as Well as the polarity of current from the battery 27 to the motor M to cause rottgzion of the motor in one direction or the ot er, according as the circuit controller andcu t-Ollt switch assume one position QIdZhE other. Thecircuit controller 200 comprises a switch blade 28 pivoted at 29 vfor engagemcut witheitherof a p irof contacts 3t) and 3].. The switch :hih-de 28 is ,actuatcd by the motor ,through the me dinm of a gear 32 fixed to the motor shaft and meshing vvith a rack bar 33. which latter is in turn CODH QCtGd to the switch blade 28. as shown.

The motor vlVI is supplied with current from a battery 10, and iscontrolled by a pole-changer 1,1 oplerated by a lever 11, which lever is usua 1y one of a plurality of similar lovers in an interlock ing machine.

The cirq i heale C s in l d inlan controls. the QlIClllt for motor M in a manner which Will appear hereinafter.

Tl16 QPQ13;JQD Qf theentire apparatus is e tellers; mediating, th sni ch is shown in the normal position, and the other parts of the apparatus are shown in the positions corrcsptmding to this position of the switch. \Vhen it is desired to move the switch 12 to its reverse position, polechangcr 11 is manually reversed, whereby current from battery 10 is supplied to motor M in such direction as to cause rotation thereof connter-clockwise. Motor M being energized, gear 32 and disk N are now caused to rotate with the motor. With the rotation of disk N, latching device I) is operated to open the contact finger F but immediately closes such contact finger by virtue of the fact that the thermostat X. remains in its normal condition. l-Vhcn gear 32 is rotated, rack bar 33 is drawn to the right, thereby shifting the switch blade 28 from contact 31 to Contact 30. It will be noted that the gear 32 and the rack bar 33 are so proportioned with respect to the disk N that the operation of latching device I), just described, is completed before switch blade 28 engages contact 30. \Vith the blade 28 in this position, current is supplied to the motor M through the following circuit: from battery 27, through wires 36 and 3?, contact 30, blade 28, wire 88, motor M, wire 35 binding post P bracket Z, screw V, wire X, trlppmg lever A, bracket Z, binding post P wire W, binding post P, contact G, contact finger F, Wire 34, blade 22, contact 25, Wires 39 and 40 to battery 27. Although current is now traversing the thermo-wire X, this Wire is so proportioned that the heat generated therein by such current is insufiicient to expand the wire to such dcgree as to cause arm A to release the circuit breaker. Furthermore, although a com aratively heavy current flows through wire while the motor M is starting, the durar tion of this heavy current is insullicicfii' to cause Wire X to expand suflieiently to trip the circuit breaker. As the slide plate [(3 approaches the end of its stroke, pin 24 abuts the end. wall of the slot 2 causing blade 22 to swing and engage contact 36 thereby exclud ng the battery 27 from the motor circuit to cause deia'nergisatien of the motor M.

To throw the swith 12 from reverse to normal position, pole-changer 11 is moved to the position shown in the drawing, whereby motor M will be energized to rotate clockwise and thereby cause the entire apparatus to operate in the same manner as when moving the switch from normal. to reverse position but in a reverse direction. By the re- Versal of the blade 28 during this reverse movement of the apparal us. motor M is then energized through the following circuit: from battery 27, wires 40 and ll, contact 31, blade 28, wire, 38, motor M, wire 35, etc. to blade 22, contact 26, wires l2 and 1513 to bat tery 27.

If the motor M should stall for any reason while moving the switch, an ex essive current will traverse the motor circuit, but such excessive current will heat the thermostatic wire X to such a drgree as to c,\- pand the same sul'liciently to cause arm A L0 trip the circuit breaker. (fontact F (i now being opened, the circuit for the motor M is of necessity disrupted, thus preventing injury to the motor or to other apparatus in the motor circuit.

Should the stalling of the motor M" be caused by some obstruction between the switch rails and track rails, it is obvious that after the wire X has cooled sntlicient ly, the pole-changer 11 may be shifted, thus 1e setting the circuit breaker and thereby cans ing the motor M to return the switch operating mechanism to its original position ready to make another attempt to crush the obstruction.

Although I have herein shown and dcscribed only one form of circuit breaker and one form of apparatus employing sm-h circuit breaker embodying my invention, it is understood that various changes and modilications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. A circuit breaker comprising a contact biased to open position, a latch for moving said contact to and holding it in closed position, a thermostat for releasing" said latch from said contact to allow the contact to open, and means for rcciprotaiting said latch to open and close the contact and to return the contact to closed position after the latter has been opened by operation of the thermostat.

2. A circuit breaker comprising a contact biased to open position, a latch cooperating therewith, means for reciprocating said latch to open and close said contact, and a thermostat for releasing said latch from said contact.

In testimony whereof I aflix my signature in presence of two witnesses.

WILLIAM H. ltIcC/LELLAND, JR.

Witnesses:

A. HERMAN WVEGNER, FAY GLASGOW.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0." 

